CN1152607C - organic electroluminescent device, organic thin film and triamine compound - Google Patents

Abstract

The present invention provides a triamine compound represented by general formula (I) and an organic electroluminescent device comprising an organic layer and a pair of electrodes placed on both sides of the organic layer, wherein the organic layer contains at least one light-emitting region and a layer hole transport layer, the layer of the hole transport region includes a hole injection layer containing the triamine compound and a hole transport layer, and provides an organic thin film comprising two layers, which are composed of the general formula (I ) represents a compound and has a thickness of 5 nm to 5 μm and a layer containing a compound represented by the general formula (II) and has a thickness of 5 nm to 5 μm. According to the present invention, it is possible to provide an organic electroluminescent device which has little possibility of dielectric breakdown after long-term storage and exhibits very high luminous efficiency, and which shows outstanding luminous stability after long-term continuous use Organic electroluminescent devices that are stable and have a long service life, and organic thin films that exhibit excellent hole injection and transport properties.

Description

Organic electroluminescent devices, organic thin films and triamine compounds

1. Technical field

The present invention relates to an organic electroluminescent device, an organic thin film and a triamine compound. More specifically, the present invention relates to an organic electroluminescence that has little possibility of dielectric breakdown after long-term storage and exhibits remarkably improved luminous efficiency due to the use of a specific triamine in the hole injection layer. A light-emitting device, an organic thin film exhibiting excellent hole injection and transport properties and ideally used in organic electroluminescent devices and photosensitive films in electrophotography, and a triamine compound that provides long life The organic electroluminescence device and the device exhibits excellent luminescence stability when a triamine compound is used for the device.

2. Background technology

An organic electroluminescent device utilizing the principle of electroluminescence exhibits high self-discrimination due to self-emission (light) and has excellent impact resistance because it is a completely solid device. Therefore, there is interest in the use of electroluminescent devices as light emitting devices in various types of displays.

The electroluminescent device includes an inorganic electroluminescent device in which an inorganic compound is used as a light-emitting substance, and an organic electroluminescent device in which an organic compound is used as a light-emitting substance. The practical applicability of the organic electroluminescent device as a next-generation display has been intensively studied because the voltage used has dropped considerably.

As for the structure of the organic electroluminescent device, the basic structure includes anode/light-emitting layer/cathode. (This specification states that the anode, light emitting layer and cathode are laminated in this order. Other structures are described in the same manner). Structures are known in which a hole injection and transport layer or an electron injection and transport layer is suitably added to the basic structure. Examples of this structure include a structure of anode/hole injection and transport layer/light emitting layer/cathode and a structure of anode/hole injection and transport layer/light emitting layer/electron injection and transport layer/cathode. The hole injection and transport layer has a role of transporting holes injected from the anode to the light emitting layer. The electron injection and transport layer has a role of transporting electrons injected from the cathode to the light emitting layer. It is known that when a hole injection and transport layer is inserted between the light emitting layer and the anode, more holes are injected into the light emitting layer in a low electric field, and electrons injected from the cathode or the electron injection and transport layer into the light emitting layer will accumulate at the interface between the hole injection and transport layer and the light emitting layer, since the hole injection and transport layer does not transport electrons. As a result, luminous efficiency is improved.

A problem with organic electroluminescent devices is that, since ultra-thin films made of organic compounds are used in organic electroluminescent devices, film crystallization causes dielectric breakdown of the devices after long-term storage.

Previously, in organic electroluminescent devices, phthalocyanine materials were generally used as hole injection materials at the interface with the anode. Phthalocyanine materials are particularly easy to crystallize among organic materials used in electroluminescent devices, and thus there is a need to develop hole injection materials that can replace phthalocyanine materials and exhibit highly amorphous properties.

In order to solve the above-mentioned problems, a technique of using a dendrimer amine as a hole-injecting material, which suppresses dielectric breakdown in the device (Japanese Patent Application Laid-Open No. Hei 4(1992)-308688) has been proposed. manual). However, this technique has a problem in that the obtained luminous efficiency is low. A technique of using an oligomer type organic semiconductor as a hole injection material has also been disclosed (the specification of European Patent No. 439627). However, this technique is not suitable for practical use because the obtained luminous efficiency is low.

Also, the above organic electroluminescent devices have a problem in that the luminance of light emission decreases after the device is continuously driven for a long period of time, and this problem is another major obstacle to the practical use of these devices.

In order to solve the above problems, technology has been disclosed which prevents the generation of leakage current and luminescence can be stably maintained for a long time by using dendritic amines (Specification of Japanese Patent Application Laid-Open No. Hei 4(1992)-308688).

However, although this technique can effectively prevent short circuits, the emission stability is not enough for practical applications.

Accordingly, it is an object of the present invention to provide an organic electroluminescence that has little possibility of dielectric breakdown after long-term storage and exhibits a remarkably improved luminous efficiency by using a material that is not easily crystallized as a hole-injecting material. device, and an organic thin film exhibiting excellent hole injection and transport properties and ideally used in organic electroluminescent devices and photosensitive films in electrophotography.

Another object of the present invention is to provide a novel compound which provides a long-lived organic electroluminescence device and which exhibits excellent light emission stability when the novel compound is used in the device.

3. Contents of the invention

As a result of intensive research to achieve the above-mentioned first object of the present invention, it was found that an organic electroluminescent device in which a specific triamine is used as a hole injection material has a small dielectric breakdown even after long-term storage possibility and show a remarkably high luminous efficiency. It was also found that an organic thin layer including two layers, which are a layer containing a specific triamine compound and having a specific thickness and a layer containing a specific compound and having a specific thickness, exhibits excellent hole injection and transport properties.

The present inventors also found that a novel triamine having a specific structure containing an aryl group can be ideally used to achieve the above-mentioned second object of the present invention.

The present invention has been accomplished based on the above findings.

Therefore, the present invention provides a kind of organic electroluminescence device, it comprises organic layer, and this organic layer comprises at least one layer of hole transport region and one layer of light-emitting region, and a pair of electrodes placed on both sides of organic layer, wherein The layer of the hole transport region includes at least a hole injection layer and a hole transport layer, and the hole injection layer contains a compound represented by the following general formula (I) and is in contact with the anode:

Wherein Ar ¹ -Ar ⁵ each represent an aryl group with 6-18 nuclear carbon atoms, they can be unsubstituted or substituted by alkyl, alkoxy, vinyl or styryl, and can be the same or different ( The number of carbon atoms on the nucleus refers to the number of carbon atoms constituting an aromatic ring among carbon atoms of an aryl group). Ar ¹ -Ar ⁵ in the general formula (I) each preferably represent an aryl group having 6 to 18 carbon atoms, which is unsubstituted or substituted by an alkyl, alkoxy, vinyl or styryl group.

In the present invention, it is preferred that the hole-transporting layer in the electroluminescent device contains a compound represented by the general formula (II):

Wherein X represents a single bond, methylene, phenylene, biphenylene, -O-, -S-, or any one of the following formulae represents a group:

and Ar ⁶ -Ar ¹⁰ each represent an aryl group having 6 to 18 carbon atoms, which may be unsubstituted or substituted by an alkyl group, an alkoxy group, a vinyl group or a styryl group, and may be the same or different.

The present invention also provides organic thin films comprising two layers. These two layers are a layer containing the compound represented by the general formula (I) and having a thickness of 5 nm to 5 μm and a layer containing the compound represented by the general formula (II) and having a thickness of 5 nm to 5 μm.

The present invention further provides triamine compounds represented by general formula (III):

wherein Ar ¹ -Ar ⁴ each represent an aryl group having 6-18 nuclear carbon atoms, which may be unsubstituted or substituted by alkyl, alkoxy, vinyl or styryl, and may be the same or different, Ar ⁵ represents an unsubstituted or substituted biphenyl group. In the triamine compound, it is preferable that Ar in the general formula (III) represents an aryl ^group represented by the following formula:

wherein R represents hydrogen, an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or a phenyl group, n represents an integer in 0-5, and when there are multiple Rs, these R may be the same or different; and Ar ¹ -Ar ⁴ each represent an aryl group represented by any one of the following formulae:

或

or

wherein R ¹ -R ⁵ each represent hydrogen, an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or a phenyl group, m represents an integer of 0-5, and p represents 0-4 Integer, q represents an integer of 0-5, x represents an integer of 0-3, y represents an integer of 0-4, and when there are multiple groups R ¹ , R ² , R ³ , R ⁴ or R ⁵ , The plurality of R ¹ , R ² , R ³ , R ⁴ or R ⁵ may be the same or different.

4. Description of drawings

Figure 1 shows the complete ¹ H-NMR spectrum of 4,4'-bis[N,N-bis-(3-tolyl)amino]-4"-phenyl-triphenylamine obtained in Example 9 picture.

Fig. 2 shows a part of the ¹ H-NMR spectrum of 4,4'-bis[N,N-bis-(3-methylphenyl)amino]-4"-phenyl-triphenylamine obtained in Example 9 magnified view of .

5. Specific implementation

The organic electroluminescent device of the present invention comprises an organic layer, the organic layer at least includes a hole transport region and a light emitting region, and a pair of electrodes placed on both sides of the organic layer, ie an anode and a cathode.

The anode in this electroluminescent device is the electrode used to inject holes into the device. As the anode, an electrode made of, for example, a metal, an alloy, a conductive compound, and a mixture of these compounds and having a large work function (4 eV or more) is preferably used. Specific examples of anode materials include, metals such as Au, and dielectrically transparent materials such as CuI, ITO, SnO ₂ and ZnO. The anode can be prepared by forming a thin film of the above materials by methods such as vapor deposition and sputtering. When light is obtained through the anode, it is preferred that the anode has a transmittance greater than 10%. It is also preferable that the resistance of the sheet as an anode is several hundred Ω/□ or lower.

The thickness of the anode is generally chosen to be 500 nm or less, preferably in the range of 10-200 nm, although the thickness depends on the material chosen.

The cathode, on the other hand, is the electrode used to inject electrons into the device. As the cathode, an electrode made of materials such as metals, alloys, conductive compounds, and mixtures of these compounds and having a small work function (4 eV or less) can be used. Specific examples of cathode materials include sodium, sodium-potassium alloys, magnesium, aluminum, lithium, magnesium/copper mixtures, aluminum- _lithium alloys, Al/ _Al2O3 mixtures, indium, and yttrium. The cathode can be prepared by forming a thin film of the above materials by methods such as vapor deposition and sputtering. When light is obtained through the cathode, it is preferred that the cathode has a transmittance greater than 10%. It is also preferable that the resistance of the sheet as a cathode is several hundred Ω/□ or lower. The thickness of the cathode is generally chosen to be 500 nm or less, preferably in the range of 10-200 nm, although the thickness depends on the material chosen.

In the device of the present invention, it is preferable that at least one of the anode and the cathode is a transparent or translucent material. By using such a material, light can be efficiently transmitted and obtained.

In the organic electroluminescent device of the present invention, the hole transport region means generally exhibiting a hole mobility of 10 ^-6 cm ² /V·s or higher when an electric field of 10 ⁴ -10 ⁶ V/cm is used Area. In the present invention, the layer of the hole transport region includes at least a hole injection layer and a hole transport layer. It is necessary that the hole injection layer contains a compound represented by the general formula (I):

as the main component.

In the above general formula (I), Ar ¹ -Ar ⁵ each represent an aryl group having 6-18 nuclear carbon atoms, preferably an aryl group having 6-18 carbon atoms, which may be unsubstituted or replaced by an alkane group, alkoxy group, vinyl group or styryl group, and may be the same or different. As the alkyl group and the alkoxy group, those each having 1 to 6 carbon atoms are more preferable, and any of linear, branched and cyclic groups may be used. Examples of such alkyl and alkoxy groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, various types of pentyl groups, various Types of hexyl, cyclopentyl, cyclohexyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, each Various types of pentyloxy, various types of hexyloxy, cyclopentyloxy, cyclohexyloxy. When an aryl group having 6 to 18 nuclear carbon atoms is substituted, single or multiple substituents may be introduced into the aromatic ring. The substituents may also be bonded together to form a ring. Examples of the aromatic ring in the aromatic group include benzene ring, naphthalene ring, acenaphthene ring, anthracene ring, fluorene ring, phenanthrene ring, pyrene ring, and biphenyl ring. Ar ¹ -Ar ⁵ may be the same or different.

Specific examples of the above compounds represented by the general formula (I) are given in Table 1.

Table 1-1A

Table 1-1B

Table 1-2A

Table 1-2B

Table 1-3A

Table 1-3B

Table 1-4A

Table 1-4B

Table 1-5A

Table 1-5B

In the electroluminescence device of the present invention, the hole injection layer may contain single or plural compounds represented by the general formula (I). What is required for obtaining efficient injection of holes is that the hole injection layer contains the compound represented by the general formula (I), and it is also required that the hole injection layer is provided in contact with the anode. The thickness of the hole injection layer is generally selected within the range of 5nm-5μm.

On the other hand, there is no particular limitation on the material used in the hole transport layer in the electroluminescent device of the present invention, and the material of the hole transport layer generally used in electroluminescent devices can be used. Examples of the material of the hole transport layer include triazole derivatives (such as those described in the specification of US Patent No. 3,112,197), oxadiazole derivatives (such as those described in the specification of US Patent No. 3,189,447), Imidazole derivatives, polyaryl alkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, 1,2-diphenylethylene derivatives, silazane derivatives, polysilanes, aniline copolymers, and conductive polymers (especially thiophene oligomers).

Aromatic tertiary amine compounds and styrylamine compounds can also be used as a material for the hole transport layer. Representative examples of such compounds include N,N,N',N'-tetraphenyl-4,4'-diaminophenyl, N,N'-diphenyl-N,N'-bis(3- Methyl-phenyl)-4,4′-diaminobiphenyl (TPDA), 2,2-bis(4-di-p-tolylaminophenyl)propane, 1,1-bis(4-di-p Tolylaminophenyl)cyclohexane, N,N,N',N'-tetra-p-tolyl-4,4'-diaminobiphenyl, 1,1-bis(4-di-p-toluene phenylaminophenyl)-4-phenylcyclohexane, bis(4-dimethylamino-2-methylphenyl)phenylmethane, bis(4-di-p-tolylaminophenyl)phenyl Methane, N,N'-diphenyl-N,N'-bis(4-methoxyphenyl)-4,4'-diaminobiphenyl, N,N,N',N'-tetraphenyl - 4,4'-diaminodiphenyl ether, 4,4'-bis(diphenylamino)terphenyl. N,N,N-tris(p-tolyl)amine, 4,4'-bis[4-(two-p-tolylamino)stilbene], 4-N,N-diphenylamino-(2, 2-diphenylvinyl)benzene, 3-methoxy-4'-N,N-diphenylaminostilbene, and N-phenylcarbazole.

In the present invention, it is particularly preferable to contain a compound represented by the general formula (II):

The layer as the main component functions as a hole transport layer. An organic electroluminescent device with higher luminous efficiency can be obtained by using this layer.

In the general formula (II), X represents a single bond, methylene, phenylene, biphenylene, -O-, -S-, or a group represented by any one of the following formulas:

There are no particular limitations on those positions on the phenylene or biphenylene that allow the phenylene or biphenylene to bond to an adjacent aromatic ring. Preferably, phenylene and biphenylene are 1,4-phenylene and 4,4-biphenylene, respectively. Ar ⁶ -Ar ¹⁰ each represent an aryl group having 6-18 nuclear carbon atoms, preferably an aryl group having 6-18 carbon atoms, which is unsubstituted or replaced by an alkyl group, an alkoxy group, a vinyl group, or substituted by styryl, that is, the same as the aryl represented by Ar ¹ -Ar ⁵ . Ar ⁶ -Ar ¹⁰ may be the same or different.

Specific examples of compounds represented by general formula (II) are shown in Table 2.

Table 2-1A

Table 2-1B

Table 2-2A

Table 2-2B

Table 2-3A

Table 2-3B

Table 2-4A

Table 2-4B

Table 2-5A

Table 2-5B

Table 2-6A

Table 2-6B

In the organic electroluminescent device of the present invention, the hole-transporting layer contains one or more of the above-mentioned compounds. The thickness of the hole transport layer is generally selected between 5nm-5μm.

In the organic electroluminescent device of the present invention, the light-emitting region refers to a region in which light-emitting molecules in a solid state become excited state and emit light.

The light-emitting molecules in the solid state are not particularly limited, and light-emitting materials generally used for organic electroluminescence devices can be used. As the luminescent material, materials having excellent film-forming properties can be used, for example, luminescent whitening agents such as luminescent whitening agents of condensed polycyclic aromatic compounds, benzoxazole luminescent whitening agents, benzothiazole Luminous brighteners, and benzimidazole luminous brighteners; metal-chelated oxanoid compounds; or distyrylbenzene compounds. Examples of condensed polycyclic aromatic compounds include condensed ring-luminescent substances having a skeleton of anthracene, naphthalene, phenanthrene, pyrene, phenanthrene, or perylene.

As the above luminous whitening agent, such as benzoxazole luminescent whitening agent, benzothiazole luminescent whitening agent, benzimidazole luminescent whitening agent, can be used by Japanese Patent Application Publication Showa 59 (1984) - Luminescent whitening agents as described in the specification for 194393. Representative examples of such luminous brighteners include benzoxazole luminous brighteners such as 2,5-bis(5,7-di-tert-amyl-2-benzoxazolyl)-1, 3,4-thiadiazole, 4,4'-bis(5,7-tert-amyl-2-benzoxazolyl)stilbene, 4,4'-bis(5,7-bis-(2-methyl Base-2-butyl)-2-benzoxazolyl)stilbene, 2,5-bis(5,7-di-tert-amyl-2-benzoxazolyl)thiophene, 2,5-bis( 5-(α,α-Dimethylbenzyl)-2-benzoxazolyl)thiophene, 2,5-bis(5,7-bis(2-methyl-2-butyl)-2-benzene (oxazolyl)-3,4-diphenyl-thiophene, 2,5-bis(5-methyl-2-benzoxazolyl)thiophene, 4,4′-bis(2-benzoxazole base) biphenyl, 5-methyl-2-(2-(4-(5-methyl-2-benzoxazolyl)phenyl)vinyl)benzoxazole, and 2-(2-( 4-Chlorophenyl)vinyl)naphtho(1,2-d)oxazole; benzothiazole light brightening agent, such as 2,2'-(p-phenylene divinylene)-bisphenyl and thiazoles; and benzimidazole light brighteners, such as 2-(2-(4-(2-benzimidazolyl)phenyl)vinyl)benzimidazole and 2-(2-(4-carboxybenzene base) vinyl) benzimidazole. Examples of other compounds used as luminescent materials include compounds described on pages 628-637 and 640 of "Chemistry of Synthetic Dyes" (1971).

As the above metal-chelated oxanoid compound, for example, compounds described in the specification of Japanese Patent Application Laid-Open Showa 63(1988)-295695 can be used. Representative examples of such compounds include metal complexes of 8-hydroxyquinoline, such as tris(8-hydroxyquinoline)aluminum, bis(8-hydroxyquinoline)magnesium, bis(benzo(f)-8-hydroxyquinoline) Quinoline) zinc, bis (2-methyl-quinoline-8-oxyl) aluminum oxide, tris (8-hydroxyquinoline) indium, tris (5-methyl-8-hydroxyquinoline) aluminum, 8- Lithium quinolate, gallium tris(5-chloro-8-quinolate), calcium bis(5-chloro-8-quinolate), and poly(zinc(II)-bis(8-hydroxyquinolate) phenonyl) methane); and dilithium epindridione.

Metal-chelated oxanoid compounds doped with polycyclic aromatic compounds described in the specifications of US Patent 5,141,671 and US Patent 5,150,006 can also be used. Specific examples of such compounds include metal chelate complexes of 8-hydroxyquinoline, such as bis(2-methyl-quinoline-8-oxyl)(phenoxy)aluminum(III), bis(2-methyl Base-quinolin-8-oxyl)(methylphenoxy)aluminum(III), bis(2-methyl-quinoline-8-oxyl)(phenylphenoxy)aluminum(III), bis(2 -Methyl-quinoline-8-oxyl)(naphthyloxy)aluminum(III), and bis(2-methyl-quinoline-8-oxyl)aluminum(III)-μ-oxo-bis( 2-Methyl-quinoline-8-oxy)aluminum(III), doped with polycyclic aromatic compounds such as perylene and dibenzoperylene.

As the light-emitting compound, other compounds can be selected and used according to the color and other properties of the desired emitted light, for example, the distyrylbenzene derivatives described in the specification of European Patent No. 0373582, the The dimethylene derivatives described in the specification, the coumarin derivatives described in the specification of Japanese Patent Application Laid-Open No. Hei 2(1990)-191694, the bismuth derivatives described in the specification of Japanese Patent Application Laid-Open No. Hei 2(1990)-252793 Styrylpyrazine derivatives, perylene derivatives described in the specification of Japanese Patent Application Laid-Open Hei 2(1990)-196885, naphthalene derivatives described in the specification of Japanese Patent Application Laid-Open Hei 2(1990)-255789, Japanese Patent Phthaloperynone derivatives described in the specification of Japanese Patent Application Laid-Open Hei 2 (1990)-289676 and Japanese Patent Application Laid-Open Hei 2 (1990)-88689, described in the specification of Japanese Patent Application Laid-Open Hei 2 (1990)-250292 styrylamine derivatives, cyclopentadiene derivatives described in the specification of Japanese Patent Application Laid-Open No. Hei 2 (1990)-289675, and polyphenyl compounds described in the specification of European Patent No. 387715.

The layer comprising the light-emitting region of the above organic compound has a layered structure of two or more layers (as required), or it can be obtained by additionally using fluorescent substances or multilayers according to the methods described in US Patent No. 4,769,292 and US Patent No. Ring aromatic compounds to the system. In this case, the above organic compound has the form of a thin film and exhibits the function of injection and a part of the function of light emission (these are the functions of the light emitting region). A fluorescent substance exists in a small amount (several percent mol or less) in a thin film of an organic compound and exhibits a part of a light-emitting function by emitting light in response to recombination of electrons and holes.

The layers of the luminescent region may consist of a single layer comprising one or more luminescent materials or a laminate of layers of each different luminescent material.

In the organic light-emitting device of the present invention, in addition to the layer of the hole transport region and the layer of the light-emitting region as described above, other layers may be formed between the anode and the cathode, if necessary, such as to improve the efficiency of electron injection from the cathode or Improves adhesion of the layer to the anode.

Preferred examples of producing the organic electroluminescent device of the present invention are described below. First, the anode is prepared by forming a thin film including the desired electrode material (such as the material of the anode) with a thickness of 500 nm or less, preferably in the range of 10-20 nm, on a suitable substrate by methods such as vapor deposition and sputtering . On the prepared anode, a thin film including a material constituting the device, that is, a thin film of a material used for a layer including a hole injection layer, a hole transport layer, and a light emitting region, is formed.

As a method of forming such a thin film, spin coating, casting, or vapor deposition can be used. Vacuum vapor deposition is preferable because a uniform film is easily obtained and formation of pinholes can be more easily prevented. The conditions for vacuum vapor deposition will vary with the type of compound used and the crystal structure and related structures that are desired to be formed in the deposited film of molecules. Generally, it is preferred that these conditions are selected within the following ranges: the temperature of the heating boat is 50-400°C, the degree of vacuum is 10-6-10-3Pa, the vapor deposition rate is 0.01-50nm/sec, and the temperature of the substrate is -50-300°C, and the film thickness is 5nm-5μm.

After forming these layers, a thin film including a cathode material is formed on the formed layer by a method such as vapor deposition or sputtering to a thickness of 500 nm or less, preferably in the range of 10 to 200 nm, to obtain a cathode. Thus, a desired electroluminescent device can be manufactured. To manufacture an electroluminescent device, the manufacturing process can be performed in reverse order.

The electroluminescent device of the present invention prepared as above will emit light by applying a DC voltage of 3-40V under the condition that the anode is connected to the positive electrode (+) and the cathode is connected to the negative electrode (-). When the connections were reversed, no current was observed and no light was emitted at all. When an alternating voltage is applied to the electroluminescent device, luminescence is observed only under conditions where the polarity of the anode is positive and that of the cathode is negative. When applying an AC voltage to an organic EL device, any type of waveform can be used.

Preferably, the device of the invention is carried on a carrier. There is no particular limitation on the carrier, and carriers commonly used in organic electroluminescence devices, such as glass, transparent plastic, and quartz, can be used.

The present invention also provides an organic thin film comprising two layers, which are a layer containing a compound represented by the general formula (I) and having a thickness of 5 nm to 5 μm and a layer containing a compound represented by the general formula (II) and having a thickness of 5 nm to 5 μm . This organic thin film has excellent hole injection and transport properties and is ideal for use in organic electroluminescent devices. This organic thin film can also be widely used in other organic devices and photosensitive films in electrophotography.

This organic thin film can be produced in the same manner as used to produce the hole injection layer and the hole transport layer in the production of the above organic electroluminescent device.

The novel triamine compound which is another object of the present invention is described below. The triamine compound of the present invention is a compound having a structure represented by general formula (III):

wherein Ar ¹ -Ar ⁴ each represent an aryl group having 6-18 nuclear carbon atoms, which may be unsubstituted or substituted by alkyl, alkoxy, vinyl or styryl, and may be the same or different, Ar ⁵ represents an unsubstituted or substituted biphenyl group.

In general formula (III), Ar ^preferably represents an aryl group represented by the following formula:

wherein R represents hydrogen, an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or a phenyl group, n represents an integer in 0-5, and when there are multiple Rs, these R may be the same or different; and Ar ¹ -Ar ⁴ each represent an aryl group represented by any one of the following formulae:

or

wherein R ¹ -R ⁵ each represent hydrogen, an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or a phenyl group, m represents an integer of 0-5, and p represents 0-4 Integer, q represents an integer of 0-5, x represents an integer of 0-3, y represents an integer of 0-4, and when there are multiple groups R ¹ , R ² , R ³ , R ⁴ or R ⁵ , The plurality of R ¹ , R ² , R ³ , R ⁴ or R ⁵ may be the same or different. Ar ¹ -Ar ⁴ may be the same or different. R represents hydrogen, an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or a phenyl group; n represents an integer in 0-5; and when there are multiple Rs, these R can be the same or different;

The alkyl group having 1 to 6 carbon atoms represented by any one of R ¹ to R ⁵ may be linear, branched or cyclic. Specific examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl radical, n-hexyl, isohexyl, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl, and the alkoxy group having 1-6 carbon atoms represented by any one of R ¹ -R ⁵ may be linear , branched or cyclic. Specific examples of the alkoxy group having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, t-butyl oxy, n-pentyloxy, isopentyloxy, n-hexyloxy, isohexyloxy, cyclopropoxy, cyclobutoxy, cyclopentyloxy, and cyclohexyloxy.

Examples of the above triamine compound represented by the general formula (III) include the following compounds:

In the above structural formula, the abbreviations represent the following groups: Me, methyl; Et, ethyl, nPr, n-propyl; iPr, isopropyl; nBu, n-butyl; sBu, sec-butyl; tBu, tert-butyl ; nPe, n-pentyl; and nHex, n-hexyl.

The present invention is described in more detail below with reference to Examples. However, the present invention is not limited to these Examples.

The preparation of embodiment 1 HI-3

(1) Add 16.5g of aniline (the product of HIROSHIMA WAKO Co., Ltd.), 50g of p-fluoronitrobenzene (the product of HIROSHIMA WAKO Co., Ltd.), 1g of copper powder in a 500ml three-necked flask, 48.9 g of anhydrous potassium carbonate, and 330 ml of DMF (dimethylformamide), were allowed to react at 150° C. for 8 hours in the resulting mixture.

After the reaction was completed, the reaction mixture was cooled, and salts were removed from the reaction mixture by filtration. The resulting filtrate was poured into 3 liters of water, and 40 g of the crystals formed were isolated by filtration. The separated crystals were dissolved in 600ml of DMF. To the resulting solution was added 8 g of 5% Pd—C, and hydrogenation was carried out at atmospheric pressure for 4 hours by bubbling hydrogen gas through the reaction mixture.

After the reaction was complete, the catalyst Pd—C was removed from the reaction mixture by filtration. The obtained filtrate was poured into 4 liters of water, and the precipitated crystals were separated by filtration to obtain 28 g of 4,4'-diamino-triphenylamine.

(2) 1.0 g of 4,4'-diamino-triphenylamine obtained in (1), 4.0 g of 3-iodotoluene (TOKYO KASEI Co., Ltd.'s product) were added to a 300 ml three-necked flask. product), 3 g of anhydrous potassium carbonate, and 1 g of copper powder (product of HIROSHIMA WAKO Co., Ltd.), and then dissolved in 200 ml of dimethyl sulfoxide (DMSO). While stirring the mixture, a reaction was performed at 200° C. in the obtained reaction mixture for 8 hours.

After the reaction was completed, the reaction mixture was filtered, and the obtained filtrate was extracted with dichloromethane. The solvent was removed from the obtained extract by using a rotary evaporator, and the residual product was purified by a chromatographic column filled with silica gel (a product of HIROSHIMA WAKO Co., Ltd.) using toluene as a developing solvent to obtain 0.78 g of bright yellow powder.

From the measurements of NMR and FD-MS (Field Diffusion Mass Spectrometry), this product was confirmed to be 4,4'-bis[N,N-bis(3-tolyl)amino]-triphenylamine (HI-3).

The preparation of embodiment 2 HI-16

Reaction and purification were carried out according to the same operating procedure as in Example 1, except that 4.0 g of 4-iodoanisole (product of HIROSHIMA WAKO Co., Ltd.) was substituted for the 3-iodo used in Example 1 (2) Substitute toluene to obtain 0.66g of bright yellow powder.

By the measurement of NMR and FD-MS (field diffusion mass spectrometry), confirm that this product is 4,4 '-bis[N,N-bis(4-methoxyphenyl)amino]-triphenylamine (HI- 16).

The preparation of embodiment 3 HI-35

(1) In a 500ml three-necked flask, add 75g of biphenyl (product of HIROSHIMA WAKO Co., Ltd.), 19.2g of orthoperiodic acid (product of HIROSHIMA WAKO Co., Ltd.), 64.3g of iodine, 230ml of acetic acid, and 7.6 ml of concentrated sulfuric acid were allowed to react at 70°C for 2 hours in the resulting mixture.

After the reaction was completed, the reaction mixture was cooled, and then poured into 1 liter of methanol while stirring methanol. Precipitated crystals were separated by filtration, followed by recrystallization using 2 liters of acetonitrile to obtain 7.2 g of 4-iodobiphenyl.

(2) Then, react and purify according to the same operating procedure as in Example 1, except that 5.0 g of 4-iodobiphenyl obtained in the above (1) replaces the 3-iodine used in Example 1 (2) Substitute toluene to obtain 0.34 g of bright yellow powder.

By the measurement of NMR and FD-MS (field diffusion mass spectrometry), confirm that this product is 4,4'-bis[N,N-bis(biphenyl-4-yl)amino]-triphenylamine (HI-35 ).

Preparation Example 1 The preparation of HT-23

Reaction and purification are carried out according to the same operating procedure as in Example 1, except that 2.0 g of N, N'-diphenyl-4,4'-benzidine replaces 4,4' used in Example 1 (2) - Diamino-triphenylamine, 1.6 g of white powder are obtained.

From NMR and FD-MS measurements, this product was confirmed to be N,N'-bis(3-methylphenyl)-N,N'-diphenyl-4,4'-benzidine (HT-23).

Preparation Example 2 The preparation of HT-39

(1) The mixture of 4-iodobiphenyl obtained in the above embodiment 3 (1) and the acetic acid of 150ml is heated to 80° C., then, in the time of 2 hours, the fuming nitric acid of 40ml is added dropwise to the In a mixture heated at 75-90°C. After the resulting mixture was stirred at this temperature for 1 hour, the mixture was cooled to 50°C, and 200 ml of methanol was added to the cooled mixture to obtain 11 g of bright yellow crystals after filtration.

The obtained product was heated at 200° C. with a mixture of 1.6 g of aniline (a product of HIROSHIMA WAKO Co., Ltd.), 100 ml of nitrobenzene, 1 g of copper powder, and 10 g of anhydrous potassium carbonate, allowing the reaction for 48 hours. The insoluble portion was then removed from the reaction product by filtration. After removing the solvent from the filtrate by vacuum distillation, the remaining product was recrystallized by using 200 ml of ethanol to obtain 8 g of crystals.

The obtained crystals were dissolved in 200 ml of DMF. To the resulting solution was added 2 g of 5% Pd—C, and a hydrogenation reaction was carried out at atmospheric pressure for 4 hours by bubbling hydrogen gas through the reaction mixture.

The insoluble portion was removed from the reaction product by filtration, and the obtained filtrate was poured into 1 liter of water saturated with sodium chloride. Precipitated crystals were separated by filtration, and reprecipitated using 500 ml of toluene to obtain 5 g of 4,4'-bis(4-aminophenyl)triphenylamine.

(2) Carry out reaction and purification according to the same operating procedure as in Example 1(2), except that 1.0 g of 4,4'-bis(4-aminophenyl)triphenylamine in the above (1) is replaced in The 4,4'-diamino-triphenylamine used in embodiment 1(2) is used, and 3.0g of iodobenzene (the product of HIROSHIMA WAKO Co., Ltd.) is substituted in embodiment 1(2) The 3-iodotoluene used was used to obtain 0.31 g of white powder.

From NMR and FD-MS measurements, this product was confirmed to be 4,4'-bis[4-(N,N-diphenylamino)phenyl]triphenylamine (HT-39).

Preparation Example 3 The preparation of DPVBi

(1) To 150 ml of carbon tetrachloride, add 10 g of 4,4′-dimethylbiphenyl (product of ALDRICH Co.), 20 g of N-bromosuccinimide (HIROSHIMA WAKO Co., Ltd. .), and 0.9 g of benzoyl peroxide (a product of HIROSHIMA WAKO Co., Ltd.), were reacted in the resulting reaction mixture at 90° C. for 2 hours while stirring.

After cooling the reaction product, the precipitated crystals were washed with 100 ml of methanol to obtain 13.2 g of 4,4'-dibromomethyl-biphenyl.

(2) Into a 300 ml three-necked flask, 1.0 g of 4,4'-dibromomethyl-biphenyl obtained in (1) above, 3.0 g of benzophenone (TOKYO KASEI Co., Ltd. product), and 0.50 g of potassium tert-butoxide (a product of HIROSHIMA WAKO Co., Ltd.), and then dissolved in 150 ml of DMSO. The resulting solution was reacted at room temperature for 2 hours while stirring the solution.

After the reaction was completed, the reaction solution was extracted with toluene, and then the solvent was removed from the extract by distillation by using a rotary evaporator. The residual product was purified by a chromatography column packed with silica gel (product of HIROSHIMA WAKO Co., Ltd.) using toluene as a developing solvent to obtain 1.1 g of white powder.

From NMR and FD-MS measurements, this product was confirmed to be 4,4'-bis(2,2-diphenyl-1-vinyl)-1,1'-biphenyl (DPVBi).

Preparation Example 4 MTDATA

Reaction and purification are carried out according to the same operating procedure as in Example 1 (2), except that 1.0 g of 4,4', 4 "-triiodotriphenylamine replaces the 3-iodine used in Example 1 (2) Toluene is used, and 1.0 g of N-(3-tolyl)-N-phenylamine (the product of ALDRICH Co.) replaces the 4,4'-diamino-triphenyl used in embodiment 1 (2) Base amine was used to obtain 0.30 g of bright yellow powder.

From NMR and FD-MS measurements, this product was confirmed to be 4,4',4"-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (MTDATA).

Preparation Example 5 Preparation of TA-1

2.0 g of N,N'-diphenyl-1,4-phenylenediamine (product of KANTOKAGAKU Co. Ltd.), 50 ml of 4-fluoronitrobenzene (HIROSHIMA WAKO Co. , Ltd.), 5 g of anhydrous potassium carbonate, and 1 g of copper powder were reacted at 200° C. for 8 hours while stirring the mixture.

After the reaction was complete, the reaction mixture was filtered. The obtained filtrate was extracted with dichloromethane, and the solvent was removed from the obtained extract by distillation. The residual product was purified by a column packed with silica gel (product of HIROSHIMA WAKO Co., Ltd.) using toluene as a developing solvent.

The obtained product was dissolved in 100 ml of dimethylformamide (DMF). To this solution, 10 g of 5 wt% Pd—C was added, and the reaction was carried out for 8 hours under a hydrogen stream. The reaction mixture was filtered, and the solvent was removed from the filtrate. The residual product was dissolved in 100 ml of iodobenzene (product of HIROSHIMA WAKO Co., Ltd.). 10 g of anhydrous potassium carbonate and 1 g of copper powder were added to the obtained solution, and a reaction was performed in the obtained reaction mixture at 200° C. for 8 hours.

After the reaction was complete, the reaction mixture was filtered. The obtained filtrate was extracted with dichloromethane, and the solvent was removed from the extract by using a rotary evaporator. The residual product was purified by a chromatography column packed with silica gel using toluene as a developing solvent to obtain 0.24 g of a yellow powder.

From the measurements of NMR and FD-MS, it was confirmed that this product was N, N'-bis[4-(N,N-diphenylamino)-phenyl]-N,N'-diphenyl-1,4 - Phenylenediamine (TA-1).

Example 4

An ITO electrode having a thickness of 100 nm was formed on a glass substrate having a size of 25 mm×75 mm×1.1 mm, and the obtained product was used as a transparent substrate. The prepared transparent substrate was washed with isopropyl alcohol by means of ultrasonic waves for 5 minutes, washed with pure water for 5 minutes, and finally washed with isopropyl alcohol by means of ultrasonic waves for 5 minutes.

The cleaned transparent substrate was fixed in a substrate holder of a commercial apparatus (product of NIPPONSHINKU GIJUTU Co., Ltd.) used for vacuum vapor deposition. The HI-3 obtained in Example 1 was loaded into an electric heating boat made of molybdenum, and the HT-23 obtained in Preparation Example 1 was loaded into another electric heating boat made of molybdenum. The DPVBi obtained in Preparation Example 3 was charged into another electric heating boat made of molybdenum. The pressure in the vacuum chamber was then reduced to 1×10 ⁻³ Pa. By successively heating each boat, HI-3, HT-23 and DPVBi were layered on the substrate by deposition with a thickness of 60nm, 23nm and 40nm, respectively.

Then the pressure of the device was adjusted to normal pressure, and tris(8-hydroxyquinoline)aluminum (Alq, the product of DOJINKAGAKU KENKYUSHO Co., Ltd.) was packed into another electric heating boat made of molybdenum. into another electrically heated boat made of molybdenum, and the silver in a basket made of tungsten. After the pressure in the device was reduced to 2×10 ⁻⁴ Pa, the boat containing Alq was first heated electrically to deposit Alq on DPVBi with a thickness of 20 nm. Then, each of magnesium and silver was evaporated in such an amount that the weight ratio of magnesium and silver was 10:1, forming a cathode composed of an alloy of magnesium and silver and having a thickness of 200 nm. Thus, an organic electroluminescent device was produced.

By connecting the ITO electrode of the device to the positive pole (+) and the cathode made of magnesium-silver alloy to the negative pole (-), and applying a certain voltage to the fabricated device, the device emits light. The following results were obtained by applying a voltage of 8 V: current density: 1.6 mA/cm ² , luminosity: 30 cd/m ² , and luminous efficiency: 0.74 lumen/W.

The fabricated devices showed high luminous efficiency.

Example 5

An organic electroluminescent device was manufactured following the same procedure as in Example 4, except that HI-16 obtained in Example 2 was used instead of HI-3 used in Example 4.

By connecting the ITO electrode of the device to the positive pole (+) and the cathode made of magnesium-silver alloy to the negative pole (-), and applying a certain voltage to the fabricated device, the device emits light. The following results were obtained by applying a voltage of 8 V: current density: 2.0 mA/cm ² , luminance: 55 cd/m ² , and luminous efficiency: 1.1 lumen/watt. The fabricated device shows high efficiency.

Example 6

An organic electroluminescent device was manufactured following the same procedure as in Example 4, except that HI-35 obtained in Example 3 was used instead of HI-3 used in Example 4.

By connecting the ITO electrode of the device to the positive pole (+) and the cathode made of magnesium-silver alloy to the negative pole (-), and applying a certain voltage to the fabricated device, the device emits light. The following results were obtained by applying a voltage of 8 V: current density: 1.8 mA/cm ² , luminance: 40 cd/m ² , and luminous efficiency: 0.87 lumen/watt. The fabricated device shows high efficiency.

Example 7

An organic electroluminescent device was manufactured following the same procedure as in Example 4, except that HT-39 obtained in Preparation Example 2 was used instead of HT-23 used in Example 4.

By connecting the ITO electrode of the device to the positive pole (+) and the cathode made of magnesium-silver alloy to the negative pole (-), and applying a certain voltage to the fabricated device, the device emits light. The following results were obtained by applying a voltage of 8V: current density: 2.1 mA/cm ² , luminosity: 38 cd/m ² , and luminous efficiency: 0.71 lumen/watt. The fabricated devices showed high luminous efficiency.

Comparative Example 1

An organic electroluminescent device was manufactured following the same procedure as in Example 4, except that MTDATA obtained in Preparation Example 4 was used instead of HI-3 used in Example 4.

By connecting the ITO electrode of the device to the positive pole (+) and the cathode made of magnesium-silver alloy to the negative pole (-), and applying a certain voltage to the fabricated device, the device emits light. The following results were obtained by applying a voltage of 8 V: current density: 2.1 mA/cm ² , luminance: 20 cd/m ² , and luminous efficiency: 0.37 lumen/watt. The fabricated devices showed low luminous efficiency.

MTDATA

Comparative Example 2

An organic electroluminescent device was manufactured following the same operating procedure as in Example 4, except that HT-23 was not laminated.

By connecting the ITO electrode of the device to the positive pole (+) and the cathode made of magnesium-silver alloy to the negative pole (-), and applying a certain voltage to the fabricated device, the device emits light. The following results were obtained by applying a voltage of 8 V: current density: 7.0 mA/cm ² , luminance: 6.0 cd/m ² , and luminous efficiency: 0.03 lumen/watt. The fabricated device showed low efficiency.

Comparative Example 3

An organic electroluminescence device was manufactured following the same procedure as in Example 4, except that TA-1 obtained in Preparation Example 5 was used instead of HI-3 used in Example 4.

By connecting the ITO electrode of the device to the positive pole (+) and the cathode made of magnesium-silver alloy to the negative pole (-), and applying a certain voltage to the fabricated device, the device emits light. The following results were obtained by applying a voltage of 8 V: current density: 1.5 mA/cm ² , luminosity: 7.0 cd/m ² , and luminous efficiency: 0.18 lumen/watt. The fabricated device showed low efficiency.

TA-1:

Comparative Example 4

An organic electroluminescent device was manufactured following the same operating procedure as in Example 4, except that BTBIBT was used instead of HI-3 used in Example 4 and DMOVCH was used instead of HT-23 used in Example 4.

By connecting the ITO electrode of the device to the positive pole (+) and the cathode made of magnesium-silver alloy to the negative pole (-), and applying a certain voltage to the fabricated device, the device emits light. The following results were obtained by applying a voltage of 8 V: current density: 1.9 mA/cm ² , luminance: 17 cd/m ² , and luminous efficiency: 0.35 lumen/watt. The fabricated device showed low efficiency.

BTBIBT:

DMOVCH:

Example 8

An undercoat layer comprising methoxymethylated nylon (product of UNITIKA Co., Ltd., trade name T-8) was formed to a thickness of 0.1 μm on the aluminum substrate. On the formed undercoat layer, a charge generation layer comprising A-type titanyl phthalocyanine and polyvinyl butyral (SEKISUI KAGAKU Co., Ltd.; trade name, BX-1) was formed to a thickness of 0.1 μm. According to the same operating procedure as in Example 4, the HI-3 obtained in Example 1 and the HT- 23 were deposited to a thickness of 60 nm and 20 nm to form hole injection films.

The electrophotographic performance of this film was evaluated by using a test device for electrostatic recording manufactured by KAWAGUCHI DENKI Co., Ltd. in the following manner. The film was charged by a -6 kV corona discharge, and the charge decayed for 3 seconds in the dark. The film was then exposed to 6 lux of white light for 5 seconds to obtain the time (in seconds) elapsed before the surface potential of the film reached 1/2 of the initial value. As a result, the half-life exposure was found to be 0.4 lux·sec.

As described above, the organic thin film of the present invention has very excellent properties required for electrophotography.

As indicated by the above results, the organic electroluminescence devices in Comparative Examples 1-4 (having a configuration based on the conventional technology) exhibited luminous efficiencies as low as 0.03-0.37 lumen/W. On the contrary, as demonstrated in Examples 4-7, the organic electroluminescence device having the construction of the present invention showed a significantly improved luminous efficiency, which was as high as 0.71-1.1 lumen/W. As is clear from Example 8, the organic thin film of the present invention exhibits excellent hole injection and transport properties.

Embodiment 9 The preparation of compound (3)

(1) Synthesis of 4,4'-diamino-4"-phenyl-triphenylamine (compound A)

Into a 500ml eggplant-shaped flask were charged 25g of 4-aminobiphenyl (product of ALDRICH Co.), 62.6g of 4-fluoronitrobenzene (product of HIROSHIMA WAKO Co., Ltd.), 0.94g of copper powder, 40.8g anhydrous potassium carbonate, and 280 ml of dimethylformamide (DMF, a product of HIROSHIMA WAKO Co., Ltd.). The resulting mixture was heated to 160°C in an oil bath under an argon flow, at which temperature the reaction was allowed to proceed for 72 hours. After completion of the reaction, the insoluble portion was removed from the reaction product by filtration, and DMF was removed from the filtrate by distillation. To the remaining product was added 1.5 liters of methanol, and the resulting mixture was heated and stirred at 60°C. The crystals formed were isolated by filtration. After repeating this operation 4 times, 33.8 g of 4,4'-dinitro-4"-phenyl-triphenylamine were obtained.

Into a 1-liter eggplant-shaped flask were charged the 4,4'-dinitro-4"-phenyl-triphenylamine obtained above, 500 ml of DMF, and 6.8 g of 5 wt% Pd-C (HIROSHIMA WAKO Co. , Ltd.). Then, under normal pressure, hydrogen is blown into the obtained mixture, and hydrogenation reaction is carried out at room temperature. After the reaction is finished, the catalyst is removed from the reaction product by filtration. The resulting reaction solution is poured into 1.5 liters of water, and the precipitated crystals were separated by filtration. The obtained crystals were extracted with 1 liter of ethyl acetate. The obtained extract was washed with water and dehydrated with anhydrous magnesium sulfate (HIROSHIMAWAKO Co., Ltd.'s product), from The solvent was removed from the dehydrated extract to obtain 25 g of the target compound: 4,4'-diamino-4"-phenyl-triphenylamine (compound A).

(2) Synthesis of compound (3)

Add 5.01 g of 4,4'-diamino-4 "-phenyl-triphenylamine (compound A) obtained in the above (1) in the eggplant-shaped flask of 500 ml, 3-iodotoluene of 25 ml ( HIROSHIMA WAKO Co., Ltd.), 16 g of anhydrous potassium carbonate, 6 g of copper powder, and 200 ml of dimethyl sulfoxide (DMSO, a product of HIROSHIMA WAKO Co., Ltd.), and the resulting reaction mixture was blown under an argon stream Reaction was carried out at 180° C. for 6 hours. After the reaction was finished, the insoluble portion was removed from the reaction product by filtration, and the obtained filtrate was extracted with 1 liter of dichloromethane. The extract was washed with water and dehydrated with anhydrous magnesium sulfate, from the dehydrated extract The solvent was removed from the liquid. The obtained product was purified by using a chromatographic column (HIROSHIMA WAKO Co., Ltd. product) filled with activated alumina to obtain 6.5 g of bright yellow powder.

From field diffusion mass spectrometry (FD-MS) and proton nuclear magnetic resonance ( ¹ H-NMR) measurements, it was confirmed that this product was 4,4′-bis[N,N-bis-(3-tolyl)amino]- 4"-Phenyl-triphenylamine. The yield is 63% (based on compound A), and the melting point is 180-181°C.

The entire curve spectrum of ¹ H-NMR is shown in FIG. 1 , and enlarged details of ¹ H-NMR are shown in FIG. 2 .

In the FD-MS measurement of this compound, a main peak was observed at m/z=711, and this corresponds to C ₅₂ H ₄₅ N ₃ =711.

Embodiment 10 Preparation of compound (20)

The same procedure as in Example 9 was carried out, except that 25 ml of 4-iodoanisole (product of HIROSHIMA WAKO Co., Ltd.) was substituted for the 3-iodotoluene used in Example 9 (2), to obtain 5.75 g of 4,4'-bis[N,N-bis(4-anisyl)amino]-4"-phenyl-triphenylamine. The yield is 52% (based on compound A), and the melting point is 201°C.

The ¹ H-NMR measurement results of this compound are given below:

DMSO-d ₆ : δ7.63～7.55(dd, 4H); 7.44～7.40(t, 2H), 7.32～7.28(t, 1H); 7.09～7.06(d, 2H); 7.04～6.94(dd, 8H ); 6.81～6.40(dd, 16H); 3.72(s, 12H)ppm.

Embodiment 11 Preparation of compound (36)

Carry out the same operating procedure as in Example 9, except that 35 g of 4-iodobiphenyl obtained in Example 3 (1) replaces the 3-iodotoluene used in Example 9 (2), obtaining 4.65 g of 4,4'-bis[N,N-di-(biphenyl)amino]-4"-phenyl-triphenylamine. Yield was 34% (based on compound A), and melting point was 277 ℃.

The ¹ H-NMR measurement results of this compound are given below:

DMSO-d ₆ : δ7.63～7.55(dd, 20H); 7.45～7.39(t, 10H), 7.32～7.27(t, 5H); 7.09～7.06(d, 10H); 7.04～6.94(dd, 8H ) ppm.

Embodiment 12 Preparation of compound (43)

(1) 4,4'-diamino-4"-(4-tolyl)-triphenylamine (compound B)

A mixture of 100 g of phenyltoluene (product of ALDRICH Co.) and 1 liter of acetic acid was heated to 80° C., and 200 ml of fuming nitric acid was added dropwise to the heated mixture at 75-90° C. within 2 hours. After the mixture was kept stirring at this temperature for 1 hour, the mixer was cooled to 50°C, and 1 liter of methanol was added to the cooled mixture to obtain 47 g of crystals. The obtained crystals were dissolved in 1 liter of DMF. To the resulting solution, 10 g of 5% Pd—C was added, and a hydrogenation reaction was performed under normal pressure for 6 hours by bubbling hydrogen gas through the reaction mixture.

The insoluble portion in the reaction mixture was removed by filtration, and the obtained filtrate was poured into 3 liters of water saturated with sodium chloride. Precipitated crystals were separated by filtration and recrystallized by using 500 ml of toluene to obtain 37 g of 4'-methyl-4-aminobiphenyl.

Then, carry out the same operating procedure as in Example 9(1), except that 25 g of 4'-methyl-4-aminobiphenyl obtained above replaces the 4-aminobiphenyl used in Example 9(1) , 22 g of 4,4'-diamino-4"-(4-methylphenyl)-triphenylamine (compound B) were obtained.

(2) Synthesis of compound (43)

Carry out the same operation procedure with embodiment 9 (2), just the compound B of 5.00g replaces the use of compound A used in embodiment 9 (2), and the iodobenzene of 25ml (HIROSHIMA WAKO Co., the product of Ltd. ) to replace the 3-iodotoluene used in Example 9(2), to obtain 6.24 g of 4,4'-bis(N,N-diphenylamino)-4"-(4-tolyl)triphenyl The yield was 68% (based on compound B), and the melting point was 171°C.

The ¹ H-NMR measurement results of this compound are given below:

DMSO-d ₆ : δ7.63～7.55(dd, 4H); 7.53～6.81(m, 20H), 7.11～7.03(dd, 4H); 7.04～6.94(dd, 8H); 2.28(s, 3H)ppm .

Embodiment 13 Preparation of compound (57)

(1) 4,4'-diamino-4"-(4-anisyl)-triphenylamine (compound C)

A mixture of 100 g of 4-phenylanisole (product of ALDRICH Co.) and 1 liter of acetic acid was heated to 80°C, and 200 ml of fuming nitric acid was added dropwise to the heated mixture at 75-90°C over 2 hours. After the mixture was kept stirring at this temperature for 1 hour, the mixture was cooled to 50°C, and 1 liter of methanol was added to the cooled mixture to obtain 51 g of crystals.

The obtained crystals were dissolved in 1 liter of DMF. To the resulting solution, 10 g of 5% Pd—C was added, and a hydrogenation reaction was performed under normal pressure for 6 hours by bubbling hydrogen gas through the reaction mixture.

The insoluble portion in the reaction mixture was removed by filtration, and the obtained filtrate was poured into 3 liters of water saturated with sodium chloride. Precipitated crystals were separated by filtration and recrystallized by using 500 ml of toluene to obtain 41 g of 4'-methoxy-4-aminobiphenyl.

Then, carry out the same operating procedure as in Example 9(1), except that 25 g of 4'-methoxy-4-aminobiphenyl obtained above replaces the 4-aminobiphenyl used in Example 9(1). Benzene was used to obtain 23g of 4,4'-diamino-4"-(4-anisyl)-triphenylamine (compound C).

(2) Synthesis of Compound (57)

Carry out the same operation procedure with embodiment 9 (2), just the compound C of 5.00g replaces the compound A used in embodiment 9 (2) and uses, and the iodobenzene of 25ml replaces use in embodiment 9 (2) 3-iodotoluene, obtain 5.58g of 4,4'-bis(N,N-diphenylamino)-4"-(4-anisyl) triphenylamine. Yield is 62% (based on compound C basis), and the melting point is 177°C.

The ¹ H-NMR measurement results of this compound are given below:

DMSO-d ₆ : δ7.62～7.55(dd, 4H); 7.53～6.80(m, 20H), 7.12～7.02(dd, 4H); 7.03～6.94(dd, 8H); 3.70(s, 3H)ppm .

Embodiment 14 Preparation of compound (70)

(1) 4,4'-diamino-4"-biphenyl-triphenylamine (compound D)

The same procedure as in Example 9(1) was carried out except that 25 g of 4-aminoterphenyl (product of TOKYO KASEI Co., Ltd.) was substituted for the 4-aminobiphenyl used in Example 9(1) Using, 14 g of 4,4'-diamino-4"-biphenyl-triphenylamine (compound D) were obtained.

(2) Preparation of Compound (70)

Carry out the same operation procedure with embodiment 9 (2), just the compound D of 5.00g replaces the compound A used in embodiment 9 (2) and uses, and the iodobenzene of 25ml replaces use in embodiment 9 (2) 3-iodotoluene, to obtain 3.21g of 4,4'-bis(N,N-diphenylamino)-4"-biphenyl-triphenylamine. Yield is 38% (based on compound D as basis calculation), and the melting point is 178°C.

The ¹ H-NMR measurement results of this compound are given below:

DMSO-d ₆ : δ7.62～7.55(dd, 4H); 7.52～6.81(m, 20H), 7.42～7.38(t, 2H); 7.31～7.27(t, 1H); 7.08～7.00(dd, 4H ); 7.09～7.06 (dd, 4H); 7.04～6.94(dd, 8H)ppm.

Example 15 Preparation of an organic electroluminescent device by using compound (3)

An ITO (Indium Tin Oxide) electrode having a thickness of 100 nm was formed on a glass substrate having a size of 25 mm×75 mm×1.1 mm, and the obtained product was used as a transparent substrate. The prepared transparent substrate was washed with isopropanol for 5 minutes by means of ultrasonic waves, washed with pure water for 5 minutes, and finally washed with isopropanol for 5 minutes by means of ultrasonic waves.

The cleaned transparent substrate was fixed in a substrate holder of a commercial apparatus (product of NIPPONSHINKU GIJUTU Co., Ltd.) used for vacuum vapor deposition. Add following compound respectively in five electric heating boats made by molybdenum: the compound (3) of 500mg, the N of 200mg, N '-diphenyl-N, N '-two (3-methylphenyl)-[ 1,1′-biphenyl]-4,4′-diamine (TPD), 200mg 4,4′-bis(2,2-diphenylvinyl)biphenyl (DPVBi), 200mg of 4,4′ - bis[2-{4-(N,N-diphenylamino)phenyl}vinyl]biphenyl (DPAVBi) and 100 mg of tris(8-quinolinolato)aluminum (Alq).

The pressure in the device was reduced to 2×10 ⁻⁴ Pa, and the boat containing compound (3) was heated to deposit compound (3) on the substrate to form a hole injection layer with a thickness of 60 nm. Then, the boat containing TPD was heated to evaporate TPD to form a hole transport layer with a thickness of 40 nm. As a next step, the two boats containing DPVBi and DPAVBi are heated simultaneously to evaporate DPVBi and DPAVBi, and a 40 nm thick mixed light-emitting layer is obtained by vapor deposition on the hole transport layer [the ratio of the two mixed components is: DPVBi:DPAVBi=40:1 (weight ratio)]. In the final step, the boat containing Alq was heated to deposit Alq on the light-emitting layer, forming an electron injection layer with a thickness of 20nm.

Then, the product obtained above was taken out of the vacuum chamber, and a mask made of stainless steel was placed on the above electron injection layer. The bonded product is fixed again on the substrate holder. 0.5g of silver wire was placed in a basket made of tungsten, and 1g of magnesium strip was placed in another boat made of tungsten. Then the pressure in the vacuum chamber was reduced to 1×10 ^-4 Pa, magnesium and silver were deposited simultaneously at the vapor deposition speeds of 1.8nm/sec and 0.1nm/sec respectively, and a mixed electrode of magnesium and silver was produced.

By connecting the ITO electrode of the fabricated device to the positive pole (+) and the cathode made of magnesium-silver alloy to the negative pole (-), apply a voltage of 8V to the fabricated device, test the emission of light, and obtain uniform blue light . The following initial properties were obtained by applying a voltage of 8 V: current density: 3.9 mA/cm ² , luminance: 170 cd/m ² , and luminous efficiency: 1.71 lumen/watt. When the initial luminance was adjusted to 100 cd/m ² , the device was continuously driven at a constant current under dry nitrogen, and the half-life (time before the luminance reached half of the initial value) was measured to be 1500 hours.

Comparative Example 5

An organic electroluminescent device was fabricated according to the same operating procedure as in Example 15, except that 4,4',4"-tris(3-methylphenylphenylamino)triphenylamine (MTDATA, published in Japanese Patent Application The compound described in the specification of No. Hei 4(1992)-308688) was used in the hole injection layer instead of the compound (3) used in Example 15.

The emission of light was tested by applying a voltage of 8 V according to the same method as used in Example 15, and uniform blue light was obtained. The following initial properties were obtained by applying a voltage of 8 V: current density: 4.0 mA/cm ² , luminance: 140 cd/m ² , and luminous efficiency: 1.37 lumen/watt. When the initial luminance was adjusted to 100 cd/m ² , the device was continuously driven at a constant current under dry nitrogen, and the half-life was measured to be 800 hours. The lifetime of this device was significantly inferior to the device made in Example 15.

Example 16

An organic electroluminescent device was fabricated according to the same procedure as that performed in Example 15, except that Compound (20) was used instead of Compound (3) used in Example 15.

Luminescence was tested according to the same method as used in Example 15, and the following initial properties were obtained by applying a voltage of 8 V: current density: 4.2 mA/cm ² , luminosity: 172 cd/m ² , and luminous efficiency: 1.61 Lumens/Watt. When the initial luminance was adjusted to 100 cd/m ² , the device was continuously driven at a constant current under dry nitrogen, and the half-life was measured to be 1300 hours.

Example 17

An organic electroluminescent device was fabricated according to the same procedure as that performed in Example 15, except that Compound (36) was used instead of Compound (3) used in Example 15.

Luminescence was tested according to the same method as used in Example 15, and the following initial properties were obtained by applying a voltage of 8 V: current density: 4.0 mA/cm ² , luminosity: 168 cd/m ² , and luminous efficiency: 1.65 Lumens/Watt. When the initial luminance was adjusted to 100 cd/m ² , the device was continuously driven at a constant current under dry nitrogen, and the half-life was measured to be 1400 hours.

Example 18

An organic electroluminescent device was fabricated according to the same procedure as that performed in Example 15, except that Compound (43) was used instead of Compound (3) used in Example 15.

Luminescence was tested according to the same method as used in Example 15, and the following initial properties were obtained by applying a voltage of 8 V: current density: 4.0 mA/cm ² , luminosity: 170 cd/m ² , and luminous efficiency: 1.71 Lumens/Watt. When the initial luminance was adjusted to 100 cd/m ² , the device was continuously driven at a constant current under dry nitrogen, and the half-life was measured to be 1500 hours.

Example 19

An organic electroluminescent device was fabricated according to the same procedure as that performed in Example 15, except that Compound (57) was used instead of Compound (3) used in Example 15.

Luminescence was tested according to the same method as used in Example 15, and the following initial properties were obtained by applying a voltage of 8 V: current density: 4.1 mA/cm ² , luminosity: 167 cd/m ² , and luminous efficiency: 1.60 Lumens/Watt. When the initial luminance was adjusted to 100 cd/m ² , the device was continuously driven at a constant current under dry nitrogen, and the half-life was measured to be 1400 hours.

Example 20

An organic electroluminescent device was fabricated according to the same procedure as that performed in Example 15, except that Compound (70) was used instead of Compound (3) used in Example 15.

Luminescence was tested according to the same method as used in Example 15, and the following initial properties were obtained by applying a voltage of 8 V: current density: 3.9 mA/cm ² , luminosity: 157 cd/m ² , and luminous efficiency: 1.58 Lumens/Watt. When the initial luminance was adjusted to 100 cd/m ² , the device was continuously driven at a constant current under dry nitrogen, and the half-life was measured to be 1300 hours.

Industrial applicability

As described above, the organic electroluminescent device of the present invention has little possibility of dielectric breakdown after long-term storage, exhibits high luminous efficiency, and is ideally used as a light-emitting device for various displays.

The thin film of the present invention exhibits excellent hole injection and transport properties, and is ideally used in organic electroluminescent devices and other organic devices and photosensitive films in electrophotography. The triamine compound of the present invention is a novel compound, and can provide an organic electroluminescent device having a long lifetime and excellent light emission stability when the compound is used for an organic electroluminescent device.

Claims (9)

1. An organic electroluminescent device comprising an organic layer, the organic layer at least comprising a hole transport region and a light emitting region, and a pair of electrodes placed on both sides of the organic layer, wherein the hole transport region The layer comprises at least a hole injection layer and a hole transport layer, and the hole injection layer contains a compound represented by the following general formula (I): Wherein Ar ¹ -Ar ⁵ each represent an aryl group with 6-18 nuclear carbon atoms, they may be unsubstituted or substituted by alkyl, alkoxy, vinyl or styryl, and may be the same or different; and in contact with the anode. 2. The organic electroluminescent device according to claim 1, wherein Ar ¹ -Ar ⁵ in the general formula (I) each represent an aryl group with 6-18 carbon atoms, which may be unsubstituted or replaced by an alkyl group , alkoxy, vinyl or styryl substitution. 3. The organic electroluminescence device according to claim 1, wherein the hole transport layer contains a compound represented by the general formula (II):

Wherein X represents a single bond, methylene, phenylene, biphenylene, -O-, -S-, or any one of the following formulae represents a group: and Ar ⁶ -Ar ¹⁰ each represent an aryl group having 6-18 nuclear carbon atoms, which may be unsubstituted or substituted by an alkyl, alkoxy, vinyl or styryl group, and may be the same or different. 4. The organic electroluminescent device according to claim 3, wherein Ar ⁶ -Ar ¹⁰ in the general formula (II) each represent an aryl group with 6-18 carbon atoms, which may be unsubstituted or replaced by an alkyl, alkane Oxy, vinyl or styryl substitution. 5. The organic electroluminescent device according to claim 1, wherein the hole injection layer and the hole transport layer each have a thickness of 5 nm to 5 [mu]m. 6. The organic electroluminescent device according to claim 3, wherein the hole injection layer and the hole transport layer each have a thickness of 5 nm to 5 [mu]m. 7. An organic thin film comprising two layers, which are a layer containing a compound represented by the general formula (I) and having a thickness of 5 nm to 5 μm and a layer containing a compound represented by the general formula (II) and having a thickness of 5 nm to 5 μm layer. 8. A triamine compound represented by the following general formula (III): wherein Ar ¹ -Ar ⁴ each represent an aryl group having 6-18 nuclear carbon atoms, which may be unsubstituted or substituted by alkyl, alkoxy, vinyl or styryl, and may be the same or different, Ar ⁵ represents an aryl group represented by the following formula:

wherein R represents hydrogen, an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, or a phenyl group, n represents an integer in 0-5, and when there are multiple Rs, these R can be the same or different. 9. The triamine compound according to claim 8, wherein Ar ¹ -Ar ⁴ each represent an aryl group represented by any one of the following formulas in the general formula (III):

or Wherein R ¹ -R ⁵ each represent hydrogen, an alkyl group having 1-6 carbon atoms, an alkyl group having 1-6 carbon atoms, or a phenyl group, m represents an integer of 0-5, and p represents an integer of 0-4 integer, q represents an integer of 0-5, x represents an integer of 0-3, y represents an integer of 0-4, and when there are multiple groups R ¹ , R ² , R ³ , R ⁴ or R ⁵ , this A plurality of R ¹ , R ² , R ³ , R ⁴ or R ⁵ may be the same or different.

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